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ok ive read the whole shebang on the VAFC-II and am really considering this once i decide to fork over the money for it

our VTEC engages at around 3500 RPM, and is meant purely for fuel economy and not so much for performance gains. the people who have installed their VAFC-II have raised their VTEC engagement points to around 5000 RPM, therefore resulting in more of a surge of power which they can actually feel more than if the VTEC was set to factory 3500 RPM

my question is how does it make the car perform better? ive searched and read all the VAFC-II threads. didnt answer my question. i was thinking that the higher intake lift would benefit only in high RPM operation, this being the reason why the engagement point is moved higher, but wouldnt our stock 3500 RPM engagement setting waste gas since it is using high-lift profile at low RPM? please help my clarify this as our SOHC VTEC is still wierd to me (i get DOHC VTEC setups completely).


Also, i read on SuperHonda.com that our VTEC is very different, in that it limits the engine to one intake valve instead of using two, then uses two when VTEC is engaged. i think its wierd but he provided some good evidence to back thisup. true or not true? and does our VTEC actually cause higher intake lift when it is engaged? or is it the valve timing that is only changed?

thanks

 
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*bump

 
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Stock VTEC engages between 2800 and 3200rpm depending on the amount of pressure placed on the accelerator.

If you raise you engagement level to 5000 rpm you will lose MASSIVE amounts of midrange and low end power. I know, I've tried it with my VAFC. Feeling the "kick" of VTEC doesn't truly help you. The part that helps is the actual amount of time that VTEC is engaged.

I have my VTEC set to engage at 4100 rpm. This feels better for me because I can't tell a difference in power between 2800 and 4000 whether VTEC is engaged or not. But I have found that 4100 provides an optimal power surge to keep your midrange power going strong.

My VAFC II hasn't been dyno tuned yet so we will have to see if my butt-dyno is correct. But that has been my findings so far.

 
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so why raise the engagement anyways? wouldnt the lower point give better low range performance?


ohhh, maybe that would take away from the high range huh.....

 
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No, because the engine doesn't begin to make power down there. You want the VTEC engagement to start where the engine begins making the most of power which is right after 4,000 RPMs.

 
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I have my VAFC II vtec output engagment on passive mode.. The guy that tuned my car said that this the best way to utilize our vtec system for our cars .This means that the VAFC II vtec output come's on with the stock vtec input from the car. You can feel a pull in the low to mid range this way. All you have to do is go to the screen where you adjust the vtec engagement points (input/output) and then press the "stick"button to the left until you see "*" marks instead of actual engagment points. I suggest using this setup if you have the VAFC II.

 
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Why even have a VAFC just to leave the vtec point the same as stock?

 
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honestly, it is kinda worthless for daily driving. But for racing, if you shift like you are suppose to, u will be landing in vtec.

 
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I've got one on order. Does it give instructions on how to play with it? Don't think I'll be getting it tuned anytime soon. I'll try that passive vtec mode.

 
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The vtec engagment stock is input, the vtec engagment on the VAFC II is output. When you set the output on the VAFC II to engage at a certain time, you get that extra "kick" or pull. As for the passive mode, it combines the two together....civic01vtec, do you have VAFC II installed and tuned??? I'm just wondering, because it's the only part that I have put on my car that has made an noticable gain...It's probably the best part for our cars for the $

 
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That's good to hear. I'll get it tuned eventually. The dh-racing crank pulley is promising huge gains as well. Supposed to be 10whp at least for dual groove, and it's down to $135 in the GB.

 
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haha, i sense the sarcasim....i wasn't talking about the VAFC-II..........i was talking about vtec engagement. He was wondering why you guys set vtec engagement so high, cuz he feels that it will be better at a lower rpm. But when racing, u shift around 6600 rpm and if you do it right you should land in vtec. If you shift too slow and land out of vtec, then you lose hp.

 
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No, I wasn't being sarcastic...I was just trying to get input from other people that have the VAFC II.

 
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Yea, I have the VAFCII, easily one of the best mods I bought.
The screen and display is pimp, the VTEC light is real pimp, and it's nice to have all that information at hand...also, don't forget that it has a built in voltmeter so that's pretty good information.

I am always changing the point on my VTEC just finding what works best, but if I'm racing I usually set it to about 4000k to 4500k.

 
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So are there instructions on how to set certain functions? I'm not getting it tuned right away.